Stump pyometra is defined as a reinfection or inflammation of uterine remnant after ovariohysterectomy. We surveyed four bitches which were serviced in the veterinary medical teaching hospital of Seoul National University. In this Paper we studied the method for diagnosis of stump pyometra by symptoms, blood tests, and ultrasound films. To detect the stump pyometra is difficult because clinical signs are verb similar to the normal pyometra. Especially symptoms could noticed be noticed even by their owner until dogs have a vaginal discharge. Blood test also were in normal range in each item except in the elevation of the number of while blood cells. We conclude ultrasonic observation add experimental laparotomy has a significant meaning to diagnosis the stump pyometra.